Spool



Jan. 13, 1959..

J. J. STERN ETAL 2,868,475

SPOOL.

Filed Nov. 3, 1954 FIG.2

v I "a,

I "o I I IIIIIIIII i i 1 INVENTORS fi sfis W 210m United. States Patent G SPOOL Jerome .l. Stei'n, Englewood, J., and Daniel D. Whyte, Brooklyn, N. Y), assignors to Wliyte Manufacturing glgo klne, New York, N. Y., a corporation of New or i Application November 3, 1954, Serial No.4 66,4 93

2 Claims. (Cl. 242-118.4)

This invention relates to spools or reels for winding and unwinding thread or wire or the like, and more particularly, to an improved light-weight spool or rejel provided with a novel internal bracing structure resisting uneven or unequal deformation'of the spool or reel under Winding and unwinding stresses.

Spools or reels of the type to which the invention is directed generally comprise a cylindrical or tubular body, which frequently has heads on each end of greater diameter than the body. The wire or thread is wound on the body in successive layers.

A convenient method of mass producing such spools or reels is to mold or die cast the same. To facilitate molding, economize in material, and lighten the vveight of the spool or reel, the tubular body is frequently formed as an outer cylinder concentric with an inner core. The inner core and outer tube or cylinder are integrally interconnected by circumferentially spaced, axially extending radial ribs.

In winding wire or thread onto such a spool, the outer tube is placed under compression as the successive convolutions are wound thereon. The radial ribs act as columns transmitting these compressive stresses to the inner core with consequent distortion of both tube and core and lack of concentricity. This results in uneven winding of the thread or wire on the spool and uneven and irregular force distribution when the spool is rotated.

To obviate the foregoing disadvantages, the present invention is directed to a light-weight thin-walled spool or reel of this general type in which the relatively thin interconnecting and bracing ribs are so constructed and arranged that compressive stresses on the outer spool or tube are translated into rotational forces on the inner core. Thus, as the outer tube is compressed during winding, for example, the stresses transmitted through the thin and flexible ribs are absorbed by rotation of the inner core relatively to the outer tube.

To effect this result, the ribs may be arranged tangential to the inner core, where the latter is a cylinder or tube, or may be so arranged as to translate quasi-radial stresses on the outer ends of the ribs into core rotating stresses on the inner ends of the ribs. For example, if the inner core is polygonal, the plane of each rib may be coplanar with a surface of the core. If the inner core is cruciform, the ribs may be normal to the outer ends of the arms. Alternatively, the ribs may be radial but formed with axially extending undulations intermediate their ends.

In all cases, the ribs are so arranged that inward stress on any rib tends to rotate the core in the same direction as inward stress on any other rib, so that the rotational stresses imparted by all the ribs are cumulative.

For a better understanding of the invention principles, reference is made to the following description of a typical'embodiment of the invention as illustrated in the accompanying drawings.

In the drawings:

Figs. 1, 2 and 3 are end elevation views of spools con- "ice structed with bracing other than that hereinafter disclosed, illustrating the unequal deformation thereof under excessive winding stresses;

Fig. 4 is a diametric sectional view, on the line 4-4 of Fig. 5. illlustrating one form of spool embodying the invention;

Fig. 5 is an axial sectional view, on the line 5-5 of Fig. 4,101? the spool of Fig. 4; and

Figs. 6, 7, 8 and 9 are diametric sectional views of modified forms of spools embodying the invention.

Figs. 1 and 2 illustrate a known type of prior art spool comprising an outer cylinder or tube A, an inner core B which is shown as a tube, and radial webs or ribs C interconnecting tubes A and B. As formed, cylinders A and B are true cylinders and concentric, as indicated by the dotted line A of Figs. 1 and 2. However, when thread or yarn, such as nylon yarn, for example, is wound on the spool, outer tube A collapses, as indicated in Fig. l, flattening between the outer ends of ribs C while the inner core B is distorted substantially as shown. This is due to the tension of the wound yarn which exerts a compression on tube A.

Such tension is due to the stretching of the yarn during winding, resulting in elongation of the yarn, and is particularly pronounced when winding yarns having a pronounced stretchability or when winding moderately stretchable yarns tightly on a spool. As the winding stress is released, the wound yarn contracts, resulting in the aforementiontd compressive stress on tube A.

The flattening of tube A between the ribs C results in even greater radial stress on the ribs, so that one or more of the ribs may collapse, as shown in Fig. 2 with concomitant distortion substantially as shown. The conditions illustrated in Figs. 1 and 2 have seriously affected the utility of hollow, ribbed spools formed of aluminum, other metals, or plastic, irrespective of the number of strengthening ribs employed.

However, the forces exerted by shrinking of the yarn back to its original length after Winding are not only sufficient to collapse hollow ribbed spools, but also solid spools. As shown in Fig. 3, the difierential in elongation and across the grain, due to such compression, tends to flatten a wooden spool D along one diameter, with subsequent loss of concentricity and shape and frequently with cracking of the wood as shown at E.

Referring to Figs. 4 and 5, which illustrate one form which the invention may take in practice, the spool 10 of the invention is illustrated as having a body comprising concentric inner and outer tubes or cylinders 15 and 2-3 respectively, tube 15 constituting the inner core and tubing 20 the outer cylinder or winding tube. Outer tube 20 may have enlarged heads as indicated at 19 although the heads may be omitted in certain cases.

In accordance with the invention, tubes or cylinders 15 and 20 are braced and interconnected by circumferentially spaced, axially extending ribs or webs 30 which are tangential to inner tube 15. In the embodiment of Figs. 4 and 5, webs 2d are plain.

When outer tube 20 is compressed as a result of winding thread, yarn, or other elongated material thereon, the inwardly directed compressive stresses on ribs 30 are translated into rotational forces acting on core 15, due to the tangential realtion of webs 30 to core 15. Thus, the compressive stresses are absorbed by relative rotation of core 15 relative to tube 20, with the inner and outer tubes remaining concentric. Collapse of tube 20 or ribs 30 is thus prevented.

Fig. 6 illustrates another form which the ribs may take in order to translate compressive stresses thereon into rotational stresses on the inner core. Referring to Fig. 6, outer tube 20 is interconnected with inner core 15 by ribs 40 which are radial and extend axially of the spool,

Each rib 40 includes a longitudinally extending undulation 45, with all the undulations extending in the same direction circumferentially of the spool. These undulations are substantially V-shaped, including webs 41 and 42, with web 41 joined to tube 20 by a radial section 43 and web 42 joined to core by a radial section 44. As tube is compressed, the compressive stress exerted radially along web 43 has a generally circumferential vector directed along web 41. This results in another generally circumferential vector being developed in web 42 in the same general circumferential direction as the vector in web 41. The vector of the stress developed in web 42 results in a circumferential pull on section 44 so that the radial stress in section 43 is translated into a rotational stress on core 15.

The arrangement of Fig. 7 is substantially similar in construction and function to that of Fig. 4, and includes a solid inner core 15' connected by ribs to an outer tube 20. The only difference in this case is that core 15' is solid, whereas core 15 of Fig. 4 is tubular.

In the arrangement of Fig. 8, the core is polygonal, such as square, and is conencted to outer tube 20 by webs 55, each of which is a continuation of one of the surfaces of the polygonal core 50. In efiect, ribs are tangential to core 50 and are actually tangential to a circular center on core 50 and having a diameter equal to the thickness of the core. Compressive stresses on tube 20, transmitted through ribs 55, exert a rotational force on core 50 to absorb the stresses without collapse of tube 20 or ribs 55.

In Fig. 9, core is cruciform, comprising perpendicularly related arms 61. Ribs connect the outer ends of' its associated arm 61. Compressive stress on core 20, transmitted through ribs 65, is applied tangentially to core 60 at the outer ends of arms 61. All of the arms apply the stress in the same direction to the core 60, so that the stresses transmitted by the ribs 65 are cumulative and tend to rotate core 60 relative to outer tube 20.

The spools shown in Figs. 4-9 may be molded or cast as an integral member from metal or plastic composition material. While the illustrative embodiments have been shown, for convenience, as having four ribs, a greater or lesser number of ribs may be utilized dependent upon design consideration.

While specific embodiments of the invention have been shown and described in detail to illustrate the application of the invention principles, it will be understood that the invention may be embodied otherwise without departing from such principles.

What is claimed is:

l. A spool comprising an outer cylindrical body, an inner core concentric with said body, and circumferentially spaced axially extending ribs, tangential to said core and integral with and interconnecting said core and body, each said ribs being offset circumferentially of the core in the same direction from a common radius of the core and body.

2. A spool in accordance with claim 1 wherein adjacent ribs are at right angles to one another.

References Cited in the file of this patent UNITED STATES PATENTS 

